Mercury remedies are kept on Wednesday: chant Om Bram Breem Braum Sah Budhaya Namah, donate green gram (moong), green cloth, and keep the weekday fast. Emerald is the graha's stone, but it should only be worn once Mercury has been established as a functional benefic for your lagna.
Budha remedies are for speech, study and nerves. Mercury governs how clearly you think and how accurately you say what you mean, so its remedies lean towards discipline of speech and support for students.
A weak Mercury shows as scattered thinking, careless speech, difficulty finishing what was started, and nervous restlessness. Wednesday practice and service to students are the classical response.
The mantra, the weekday fast and the charity are safe for anyone — they address Mercury without amplifying it. Emerald is not: a planetary gem strengthens whatever the graha is already doing, so it needs a chart reading first.
Wednesday. Fasting, charity and mantra japa for Mercury all belong to that day.
The classical Sankhya is 9,000 repetitions, completed over weeks rather than at once. Begin with one mala — 108 — a day and build up; sincerity matters more than arithmetic.
Most charts should not wear Emerald at all. It is prescribed only where the node's dispositor is strong, where it sits in an upachaya house, and for a specific purpose named by a qualified astrologer.